Question

Determine o valor das expressões:
a) –5mn+3,7mn=

c) 5b2 - (-4b2 + 7b2) + (- b2+ 9b2 - 11b2) – (- b2 + 3b2) =

d) (7x – 2xy -5y) - (- 2x + 4xy +y) + (4x - y) =


h)–10abc+11abc=
=

i) 6ax – 4x2 + 2ax – a2 - 3ax – 3x2

Answer 1

Explicação passo-a-passo:

a) -5mn + 3,7mn = -1,3mn

b)

5b² - (-4b² + 7b²) + (-b² + 9b² - 11b²) - (-b² + 3b²)

= 5b² - 3b² - 3b² - 2b²

= 2b² - 5b²

= -3b²

c)

(7x - 2xy - 5y) - (-2x + 4xy + y) + (4x - y)

= 7x - 2xy - 5y + 2x - 4xy - y + 4x - y

= 7x + 2x + 4x - 2xy - 4xy - 5y - y - y

= 13x - 6xy - 7y

d) -10abc + 11abc = abc

e)

6ax - 4x² + 2ax - a² - 3ax - 3x²

= -4x² - 3x² + 6ax + 2ax - 3ax - a²

= -7x² + 5ax - a²

Answer 2

Oie, Td Bom?!

a)

$= - 5mn + 3,7mn$

$= (- 5 + 3,7)mn$

$= - 1,3mn$

c)

$= 5b {}^{2} - ( - 4b {}^{2} + 7b {}^{2} ) + ( - b {}^{2} + 9b {}^{2} - 11b {}^{2} ) - ( - b {}^{2} + 3b {}^{2} )$

$= 5b {}^{2} - 3b {}^{2} + ( - 3b {}^{2} ) - 2b {}^{2}$

$= 5b {}^{2} - 3b {}^{2} - 3b {}^{2} - 2b {}^{2}$

$= (5 - 3 - 3 - 2)b {}^{2}$

$= - 3b {}^{2}$

d)

$= (7x - 2xy - 5y) - ( - 2x + 4xy + y) + (4x - y)$

$= 7x - 2xy - 5y + 2x - 4xy - y + 4x - y$

$=(7 + 2 + 4)x - ( - 2 - 4)xy -( - 5 - 1 - 1)y$

$= 13x - 6xy - 7y$

h)

$= - 10abc + 11abc$

$= ( - 10 + 11)abc$

$= abc$

i)

$= 6ax - 4x {}^{2} + 2ax - a {}^{2} - 3ax - 3x {}^{2}$

$= (6 + 2 - 3)ax - ( - 4 - 3)x {}^{2} - a {}^{2}$

$= 5ax - 7x {}^{2} - a {}^{2}$

Att. Makaveli1996